Turn table for spindle motor and spindle motor having the same

ABSTRACT

Disclosed is a turn table for a spindle motor, the turn table including a clamping plate having a locking protrusion protruding from an inner surface of a first recess that is concavely formed in an outer circumference of the clamping plate, and a turn-table body having a second recess to receive the clamping plate and having protrusions that protrude from an inner surface defined by the second recess towards the first recess to lock an upper surface and a side surface of the locking protrusion.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit under 35 U.S.C. §119 of KoreanApplication No. 10-2011-0003569, filed Jan. 13, 2011, which is herebyincorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a turn table for a spindle motor and aspindle motor having the turn table.

2. Description of the Related Art

Recently, technical development of an optical disc drive (ODD) forrecording or reading data in or from an optical disc is being conducted.

The ODD includes a spindle motor for rotating an optical disc, anoptical pickup module for reading or recording data from or in theoptical disc, and a stepping motor for moving the optical pickup modulein a radial direction of the optical disc.

The spindle motor for rotating the optical disc includes a turn tablecoupled to a rotating shaft to support the optical disc. The turn tableincludes a clamping plate comprising a metallic plate. The clampingplate is attached to a magnet of a damper disposed above the opticaldisc.

Conventionally, the clamping plate is stuck to the turn table using anadhesive. However, as detachable attachment of the damper to theclamping plate is repetitively performed, the clamping plate may beundesirably separated from the turn table.

BRIEF SUMMARY

Accordingly, the present invention is to provide a turn table for aspindle motor capable of inhibiting undesirable separation of a clampingplate, and a spindle motor having the turn table.

In an aspect of the present invention, there is provided a turn tablefor a spindle motor, the turn table comprising a clamping plate having alocking protrusion protruding from an inner surface of a first recessthereof, the first recess being concavely formed in an outercircumference of the clamping plate; and a turn-table body having asecond recess to receive the clamping plate and having protrusions, theprotrusions protruding from an inner surface defined by the secondrecess towards the first recess to lock an upper surface and a sidesurface of the locking protrusion.

In another aspect, there is provided a spindle motor, the spindle motorcomprising a bearing assembly including a bearing and a housing forreceiving the bearing; a stator secured to an outer circumference of thehousing; a rotating shaft inserted into the bearing; a rotor coupled tothe rotating shaft; and a turn table including a clamping plate having alocking protrusion protruding from an inner surface of a first recessthereof, the first recess being concavely formed in an outercircumference of the clamping plate, and a turn-table body coupled tothe rotating shaft and having a second recess to receive the clampingplate and having protrusions, the protrusions protruding from an innersurface defined by the second recess towards the first recess to lock anupper surface and a side surface of the locking protrusion.

In a further aspect, there is provided a spindle motor, the spindlemotor comprising a bearing assembly including a bearing and a housingfor receiving the bearing; a stator secured to an outer circumference ofthe housing; a rotating shaft inserted into the bearing; a rotor coupledto the rotating shaft; and a turn table including a clamping platehaving a locking protrusion protruding from an inner surface of a firstrecess thereof; the first recess being concavely formed in an outercircumference of the clamping plate, and a turn-table body coupled tothe rotating shaft and having a second recess to receive the clampingplate and having protrusions, the protrusions protruding from an innersurface defined by the second recess towards the first recess to lock anupper surface and a side surface of the locking protrusion, wherein theprotrusions comprise a first protrusion facing the upper surface of thelocking protrusion, and a second protrusion facing the side surface ofthe locking protrusion to inhibit rotation of the clamping plate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing a spindle motor in accordance with anembodiment of the present invention;

FIG. 2 is an exploded perspective view showing a turn table;

FIG. 3 is an enlarged view showing portion ‘A’ encircled in FIG. 2; and

FIGS. 4 and 5 are plan views showing a process of assembling a clampingplate with a clamp portion, in accordance with an embodiment of thepresent invention.

DETAILED DESCRIPTION

FIG. 1 is a sectional view showing a spindle motor in accordance with anembodiment of the present invention.

The spindle motor 200 includes a bearing assembly 210, a stator 220, arotating shaft 230, a rotor 240, and a turn table 260. In addition tothese components, the spindle motor 200 may further include a suctionmagnet 250, a base plate 215 and a circuit board 216.

The bearing assembly 210 includes a bearing housing 211 and a bearing214.

The bearing housing 211 takes a shape of a cylinder that is open at atop thereof; and may be fabricated by pressing a metallic plate, forexample. Otherwise, the bearing housing 211 may be formed using castbrass.

The bearing housing 211 taking the shape of the cylinder that is open atthe top includes a side plate 212 and a bottom plate 213.

The side plate 212 of the bearing housing 211 is shaped like a cylinder,for example, and the bottom plate 213 is provided on a lower end of theside plate 212. According to an embodiment of the present invention, theside plate 212 and the bottom plate 213 may be integrated into a singlestructure by pressing.

An upper end of the side plate 212 of the bearing housing 211 is bentoutwards from the side plate 212. A bent portion functions to fix a coreof a stator 220 that will be described below.

The bearing 214 is received in a space defined in the bearing housing211, and takes a shape of a cylinder having a shaft insertion hole intowhich a rotating shaft 230 is inserted. The bearing 214 may comprise,for example, an oil impregnated sintered bearing.

The bearing housing 211 of the bearing assembly 210 is coupled to thebase plate 215. A burring portion 217 is formed on the base plate 215,and the side plate 212 of the bearing housing 211 is press-fitted intothe burring portion 217. The circuit board 216 electrically connected toa coil of the stator 220 is disposed on an upper surface of the baseplate 215.

The stator 220 includes a core 221 and a coil 225.

The core 221 is formed by stacking up a plurality of thin steel sheets,with a through hole being formed in a central portion of the core 221 tobe coupled to the side plate 212 of the bearing housing 211.

The coil 225 is wound around the core 221, and generates a magneticfield as a driving signal is transmitted from the circuit board 216 tothe coil 225 wound around the core 221.

An upper surface of the core 221 makes contact with the portion bentfrom the side plate 212 of the bearing housing 211. Hence, the core 221is fixed to the side plate 212 of the bearing housing 211.

The rotating shaft 230 is rotatably supported in the shaft insertionhole of the bearing 214 received in the bearing housing 211.

The rotor 240 includes a yoke 245 and a magnet 248.

The yoke 245 takes a shape of a cylinder which is open at a bottomthereof. To be specific, the yoke 245 includes a top plate 242 and aside plate 244.

The top plate 242 of the yoke 245 is formed to take a shape of a thindisc, with a yoke burring portion 243 being formed on a central portionof the top plate 242. The yoke burring portion 243 is coupled to therotating shaft 230. As the yoke burring portion 243 is coupled to therotating shaft 230, the top plate 242 of the yoke 245 rotates along withthe rotating shaft 230.

The side plate 244 of the yoke 245 extends from an outer edge of the topplate 242 to surround the stator 200.

The magnet 248 is disposed along an inner surface of the side plate 244facing the core 221. The yoke 245 is rotated along with the rotatingshaft 230 by attractive force or repulsive force between a magneticfield generated from the magnet 248 and a magnetic field generated fromthe coil 225 wound around the core 221.

The suction magnet 250 is disposed on an inner surface of the top plate242 of the yoke 245 that faces the core 221. When viewed on a plane, thesuction magnet 250 is shaped like a ring. The suction magnet 250 sucksthe bearing housing 211 to inhibit the yoke 245 from floating.

FIG. 2 is an exploded perspective view showing the turn table. FIG. 3 isan enlarged view showing portion ‘A’ encircled in FIG. 2.

The turn table 260 is placed on the top plate 242 of the yoke 245 and iscoupled to the rotating shaft 230, so that the turn table 260 rotatesalong with the rotating shaft 230.

In an embodiment of the present invention, the turn table 260 includes aturn-table body 261 for fixing an optical disc and a clamping plate 270.

The clamping plate 270 takes a shape of a disc having inner and outercircumferences. A first recess 271 is concavely formed in a directionfrom the outer circumference to the inner circumference of the clampingplate 270.

According to an embodiment of the present invention, three firstrecesses 271 are formed at regular intervals. A locking protrusion 273protrudes from a bottom facing the turn-table body 261 on an innersurface defined by each first recess 271. The locking protrusion 273 isformed in every first recess 271.

The clamping plate 270 may comprise a metallic plate, for example, togenerate a suction force by interaction with the magnet. Alternatively,the clamping plate 270 may include a magnet.

The turn-table body 261 includes a clamp portion 264, a burring portion266 and a support portion 268.

According to an embodiment of the present invention, the clamp portion264 has a second recess 264 a that is suitable to receive the clampingplate 270. The second recess 264 a defines an inner surface 264 b and abottom surface 264 c in the clamp portion 264. Here, the inner surface264 b faces the outer circumference of the clamping plate 270, and thebottom surface 264 c faces a bottom of the clamping plate 270.

Protrusions 265 are formed on the inner surface 264 b defined by thesecond recess 264 a of the clamp portion 264. The protrusions 265 facean upper surface 273 b and a side surface 273 a of the lockingprotrusion 273 of the clamping plate 270, respectively.

The protrusions 265 are disposed to face the upper surface 273 b and theside surface 273 a of the locking protrusion 273 of the clamping plate270, respectively, thus inhibiting the clamping plate 270 from beingremoved from the clamp portion 264 or being undesirably moved in theclamp portion 264.

The protrusions 265 comprise a first protrusion 265 a and a secondprotrusion 265 b.

The first protrusion 265 a protrudes from the inner surface 264 a of theclamp portion 264, and the second protrusion 265 b is arranged to beparallel to the first protrusion 265 a in such a way that the secondprotrusion 265 b does not overlap the first protrusion 265 a.

A lower surface of the first protrusion 265 a is disposed to face ormake contact with the upper surface of the locking protrusion 273, andthe second protrusion 265 b is disposed to face or make contact with theside surface of the locking protrusion 273.

The upper surface of the second protrusion 265 b is disposed to be lowerthan the upper surface of the first protrusion 265 a. The upper surfaceof the second protrusion 265 b is disposed at a position correspondingto the lower surface of the first protrusion 265 a, for example. Thesecond protrusion 265 b inhibits the clamping plate 270 from rotating.

Further, the first protrusion 265 a is thick enough to inhibit itselastic deformation by an external force, whereas a thickness of thesecond protrusion 265 b is set to allow the second protrusion 265 b tobe easily elastically deformed by an external force and restored to itsoriginal state.

Meanwhile, the lower surface of the second protrusion 265 b and thebottom surface 264 c of the clamp portion 264 corresponding to the lowersurface of the second protrusion 265 b have an escape space 265 c topermit the elastic deformation of the second protrusion 265 b, and anopening is formed through the bottom surface 264 c at a positioncorresponding to the first protrusion 265 a.

FIGS. 4 and 5 are plan views showing a process of assembling theclamping plate with the clamp portion according to an embodiment of thepresent invention.

Referring to FIG. 4, in order to assemble the clamping plate with theclamp portion, the locking protrusion 273 formed in the first recess 271of the clamping plate 270 is placed above the second protrusion 265 b,and force is applied to the clamping plate 270 towards the bottomsurface 264 c of the clamp portion 264. Therefore, the second protrusion265 b is elastically deformed towards the bottom surface 264 c, thuscausing the upper surface 273 b of the locking protrusion 273 to moveunder the lower surface of the first protrusion 265 a.

After the upper surface 273 b of the locking protrusion 273 has movedunder the lower surface of the first protrusion 265 a, the upper surface273 b of the locking protrusion 273 moves to the lower surface of thefirst protrusion 265 a.

Referring to FIG. 5, as the upper surface 273 b of the lockingprotrusion 273 moves to the lower surface of the first protrusion 265 a,the second protrusion 265 b elastically deformed by the lockingprotrusion 273 returns to its original position. Thereby, the lockingprotrusion 273 is disposed between the first protrusion 265 a and thesecond protrusion 265 b. Consequently, the locking protrusion 273 is notremoved from the clamp portion 264 by the first and second protrusions265 a and 265 b.

According to an embodiment of the present invention, among the sidesurfaces of the locking protrusion 273, a side surface facing the firstprotrusion 265 a is formed to be inclined, thus allowing the lockingprotrusion 273 to more easily slide to the lower surface of the firstprotrusion 265 a.

As described above, the present invention provides a turn table for aspindle motor and a spindle motor having the turn table, in which alocking protrusion provided on a clamping plate is locked using twoprotrusions provided in a clamp portion having a recess for receivingthe clamping plate, thus inhibiting the clamping plate from beingunexpectedly removed from the clamp portion.

Although the preferred embodiments of the present invention have beendisclosed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims.

1. A turn table for a spindle motor, comprising: a clamping plate havinga locking protrusion protruding from an inner surface of a first recessthereof, the first recess being concavely formed in an outercircumference of the clamping plate; and a turn-table body having asecond recess to receive the clamping plate and having protrusions, theprotrusions protruding from an inner surface defined by the secondrecess towards the first recess to lock the locking protrusion.
 2. Theturn table as set forth in claim 1, wherein the clamping plate takes ashape of a disc, and the first recess comprises three first recessesthat are formed at regular intervals on the outer circumference of theclamping plate.
 3. The turn table as set forth in claim 1, wherein theprotrusions comprise: a first protrusion facing an upper surface of thelocking protrusion; and a second protrusion facing a side surface of thelocking protrusion to inhibit rotation of the clamping plate.
 4. Theturn table as set forth in claim 3, wherein an upper surface of thesecond protrusion is disposed to be lower than an upper surface of thefirst protrusion.
 5. The turn table as set forth in claim 3, wherein theupper surface of the second protrusion is disposed under a lower surfaceof the first protrusion.
 6. The turn table as set forth in claim 3,wherein a thickness of the second protrusion is set to allow the secondprotrusion to be elastically deformed.
 7. The turn table as set forth inclaim 3, wherein a side surface of the locking protrusion facing thefirst protrusion is formed to be inclined.
 8. The turn table as setforth in claim 1, wherein an escape space is formed under theprotrusions to receive the locking protrusion.
 9. The turn table as setforth in claim 1, wherein the protrusions lock an upper surface and aside surface of the locking protrusion, respectively.
 10. A spindlemotor, comprising: a bearing assembly including a bearing and a housingfor receiving the bearing; a stator secured to an outer circumference ofthe housing; a rotating shaft inserted into the bearing; a rotor coupledto the rotating shaft; and a turn table including: a clamping platehaving a locking protrusion protruding from an inner surface of a firstrecess thereof, the first recess being concavely formed in an outercircumference of the clamping plate; and a turn-table body coupled tothe rotating shaft and having a second recess to receive the clampingplate and having protrusions, the protrusions protruding from an innersurface defined by the second recess towards the first recess to lock anupper surface and a side surface of the locking protrusion.
 11. Thespindle motor as set forth in claim 10, wherein the clamping plate takesa shape of a disc, and the first recess comprises three first recessesthat are formed at regular intervals on the outer circumference of theclamping plate.
 12. The spindle motor as set forth in claim 10, whereinthe protrusions comprise: a first protrusion facing an upper surface ofthe locking protrusion; and a second protrusion facing a side surface ofthe locking protrusion to inhibit rotation of the clamping plate. 13.The spindle motor as set forth in claim 12, wherein an upper surface ofthe second protrusion is disposed to be lower than an upper surface ofthe first protrusion.
 14. The spindle motor as set forth in claim 12,wherein the upper surface of the second protrusion is disposed under alower surface of the first protrusion.
 15. The spindle motor as setforth in claim 12, wherein a thickness of the second protrusion is setto allow the second protrusion to be elastically deformed.
 16. Thespindle motor as set forth in claim 12, wherein a side surface of thelocking protrusion facing the first protrusion is formed to be inclined.17. The spindle motor as set forth in claim 10, wherein an escape spaceis formed under the protrusions to receive the locking protrusion.
 18. Aspindle motor, comprising: a bearing assembly including a bearing and ahousing for receiving the bearing; a stator secured to an outercircumference of the housing; a rotating shaft inserted into thebearing; a rotor coupled to the rotating shaft; and a turn tableincluding: a clamping plate having a locking protrusion protruding froman inner surface of a first recess thereof, the first recess beingconcavely formed in an outer circumference of the clamping plate; and aturn-table body coupled to the rotating shaft and having a second recessto receive the clamping plate and having protrusions, the protrusionsprotruding from an inner surface defined by the second recess towardsthe first recess to lock an upper surface and a side surface of thelocking protrusion, wherein the protrusions comprise: a first protrusionfacing the upper surface of the locking protrusion; and a secondprotrusion facing the side surface of the locking protrusion to inhibitrotation of the clamping plate.
 19. The spindle motor as set forth inclaim 18, wherein an upper surface of the second protrusion is disposedto be lower than an upper surface of the first protrusion.
 20. Thespindle motor as set forth in claim 18, wherein the upper surface of thesecond protrusion is disposed under a lower surface of the firstprotrusion.